At present, a box-like trailer (a semi-trailer and a box-like full-trailer) at both home and abroad is usually a box-like trailer constructed by mounting a compartment framework and skins onto a chassis of a flat-plate trailer. The frame of a trailer is typically a trapezoid frame constituted by large-size I-beam steel and channel steel. A sealing compartment is additionally mounted onto the frame to form a non-integral vehicle body. The whole load of the entire vehicle is borne by the frame. The sealing compartment on the frame is unable to share the loads borne by the frame, rather, the weight of the compartment is entirely loaded on the frame to add loads on the frame. It is reasonable for a frame constituted by large-size I-beam steel and channel steel to be used for a cargo carrying vehicle and a flat-plate or fence-plate semi-trailer or full trailer. However, such design of toy bricks in which a frame is additionally mounted with a sealing compartment to form a sealing box-like semi-trailer or full-trailer can cause some problems. When the vehicle is fully loaded, the main beam of the frame will necessarily go through an alternating up-and-down elastic deformation, with a normal deforming extent of 50-80 mm. However, the sealing compartment on the frame will not go through such a harmonious deformation in synchronization with the frame, which would indefinitely produce very large shearing force acting on the framework and skins of the sealing compartment, resulting in the cracking of frame weld openings and the loosening and slipping off of skin rivets. During vehicle running, the cracking of weld openings and the loosening and slipping off of skin rivets occur frequently and repeatedly, thus having a serve influence on the safety of driving. This originates from the initial disadvantages of the unreasonable design of toy bricks and the only way to solve this problem is to adopt a structure of an integral vehicle body.